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49 Andromedae
49 Andromedae is a star in the constellation Andromeda. ''49 Andromedae'' is the Flamsteed designation (abbreviated 49 And), though it also bears the Bayer designation A Andromedae. It is visible to the naked eye under good viewing conditions with an apparent visual magnitude of 5.269. The distance to 49 Andromedae, as determined from its annual parallax shift of , is around 333 light-years. It is drifting closer to the Sun with a heliocentric radial velocity of −11.5 km/s. With an estimated age of years, this is an aging red-clump giant star with a stellar classification of K0 III, indicating it is generating energy by helium fusion at its core. The spectrum displays "slightly strong" absorption lines of cyanogen (CN). It has 2.07 times the mass of the Sun and has expanded to 11 times the Sun's radius. The star is radiating 71 times the Sun's luminosity from its enlarged photosphere at an effective temperature of . It is spinning with a pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andromeda (constellation)
Andromeda is one of the 48 constellations listed by the 2nd-century Greco-Roman astronomer Ptolemy, and one of the 88 modern constellations. Located in the northern celestial hemisphere, it is named for Andromeda, daughter of Cassiopeia, in the Greek myth, who was chained to a rock to be eaten by the sea monster Cetus. Andromeda is most prominent during autumn evenings in the Northern Hemisphere, along with several other constellations named for characters in the Perseus myth. Because of its northern declination, Andromeda is visible only north of 40° south latitude; for observers farther south, it lies below the horizon. It is one of the largest constellations, with an area of 722 square degrees. This is over 1,400 times the size of the full moon, 55% of the size of the largest constellation, Hydra, and over 10 times the size of the smallest constellation, Crux. Its brightest star, Alpheratz (Alpha Andromedae), is a binary star that has also been counted as a part ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Absorption Line
Absorption spectroscopy is spectroscopy that involves techniques that measure the absorption (electromagnetic radiation), absorption of electromagnetic radiation, as a function of frequency or wavelength, due to its interaction with a sample. The sample absorbs energy, i.e., photons, from the radiating field. The intensity of the absorption varies as a function of frequency, and this variation is the #Absorption spectrum, absorption spectrum. Absorption spectroscopy is performed across the electromagnetic spectrum. Absorption spectroscopy is employed as an analytical chemistry tool to determine the presence of a particular substance in a sample and, in many cases, to quantify the amount of the substance present. Infrared spectroscopy, Infrared and ultraviolet–visible spectroscopy are particularly common in analytical applications. Absorption spectroscopy is also employed in studies of molecular and atomic physics, astronomical spectroscopy and remote sensing. There is a wide r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bayer Objects
Bayer AG (English: , commonly pronounced ; ) is a German multinational pharmaceutical and biotechnology company and is one of the largest pharmaceutical companies and biomedical companies in the world. Headquartered in Leverkusen, Bayer's areas of business include: pharmaceuticals, consumer healthcare products, agricultural chemicals, seeds and biotechnology products. The company is a component of the EURO STOXX 50 stock market index. Bayer was founded in 1863 in Barmen as a partnership between dye salesman Friedrich Bayer (1825–1880) and dyer Friedrich Weskott (1821–1876). The company was established as a dyestuffs producer, but the versatility of aniline chemistry led Bayer to expand its business into other areas. In 1899, Bayer launched the compound acetylsalicylic acid under the trademarked name Aspirin. Aspirin is on the World Health Organization's List of Essential Medicines. In 2021, it was the 34th most commonly prescribed medication in the United State ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horizontal-branch Stars
The horizontal branch (HB) is a stage of stellar evolution that immediately follows the red-giant branch in stars whose masses are similar to the Sun's. Horizontal-branch stars are powered by helium fusion in the core (via the triple-alpha process) and by hydrogen fusion (via the CNO cycle) in a shell surrounding the core. The onset of core helium fusion at the tip of the red-giant branch causes substantial changes in stellar structure, resulting in an overall reduction in luminosity, some contraction of the stellar envelope, and the surface reaching higher temperatures. Discovery Horizontal branch stars were discovered with the first deep photographic photometric studies of globular clusters and were notable for being absent from all open clusters that had been studied up to that time. The horizontal branch is so named because in low-metallicity star collections like globular clusters, HB stars lie along a roughly horizontal line in a Hertzsprung–Russell diagram. Because the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
K-type Giants
K-type may refer to: *AEC K-type The AEC K-type was a type of bus chassis built by Associated Equipment Company (AEC) from 1919 until 1926, mainly for use in London by the London General Omnibus Company (LGOC). Description The K-type was an important design that ended the ..., a bus chassis * K-type star, a stellar spectral classification * K-type filter, a type of electronic filter * K-type asteroid, an unusual kind of asteroid {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xi Andromedae
Xi Andromedae is a solitary star in the northern constellation of Andromeda. It has the proper name Adhil, pronounced ; the Bayer designation is Latinized from ξ Andromedae, abbreviated Xi And or ξ And, respectively. The star has an apparent magnitude of +4.9, which is bright enough to be faintly visible to the naked eye at night. Based on parallax measurements obtained during the Gaia mission, it lies at a distance of roughly from the Sun. It is drifting closer with a heliocentric radial velocity of –12.6 km/s. Nomenclature ''ξ Andromedae'' ( Latinised to ''Xi Andromedae'') is the star's Bayer designation. It also bears the Flamsteed designation ''46 Andromedae''. Johann Bayer labeled this star "ξ" in his '' Uranometria''. The star appeared in John Flamsteed's '' Atlas Coelestis'', but was unlabeled. It was later designated as ''46 And'' by Jérôme Lalande. The label "ξ" was used in ''Atlas Coelestis'', apparently erroneously, for what Bayer had labeled " ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Train (clothing)
In clothing, a train describes the long back portion of a robe, coat, cloak, skirt, overskirt, or Dress (garment), dress that trails behind the wearer. It is a common part of ceremonial robes in academic dress, court dress or Court uniform and dress in the United Kingdom, court uniform. It is also a common part of a woman's formal evening gowns or wedding dresses. Types of train Fashion * Court train – Worn for formal court occasions, the court train had to fall in with strict dress codes which differed from court to court. For example, the French court code set in 1804 by Jean-Baptiste Isabey prescribed a four-inch maximum width for embroidered train borders for non-Royal wearers. In Britain it was required to be three yards in length at the minimum.''Dress and Insignia Worn at His Majesty's Court''. Various editions 1898-1937 * Double train – Two trains attached to the same dress, or a single train divided into two trains. * Fishtail train – A train popular at various ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adhil
The name Adhil has been applied to a number of stars, especially the star of Xi Andromedae in the constellation of Andromeda. It is the name approved by the International Astronomical Union for Xi Andromedae. Origin ''Adhil'' was originally applied to the description of Ptolemy's 21st and 22nd of Andromeda in his star catalogue in Latin translated version of ''Almagest''. :Etymology :''Adhil'' is a lingua franca term from an Arabic phrase ''al-dhayl'' að-ðáil">/nowiki>að-ðáil/nowiki> meaning "the train f a garment (literally "the tail"). :Identification :There are two kind of the identification of Ptolemy's 21st and 22nd of Andromeda. Renaissance times However Bayer gave ''Adhil'' for 60/b And in his prominent work ''Uranometria'' in 1603, and Bode followed Bayer in his great star atlas '' Uranographia'' in 1801. Recent times ''Adhil'' is applied to Xi Andromedae from Manitius' identification of Ptolemy's 21st of Andromeda. See also * Xi Andromedae (recent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Projected Rotational Velocity
Stellar rotation is the angular motion of a star about its axis. The rate of rotation can be measured from the spectrum of the star, or by timing the movements of active features on the surface. The rotation of a star produces an equatorial bulge due to centrifugal force. As stars are not solid bodies, they can also undergo differential rotation. Thus the equator of the star can rotate at a different angular velocity than the higher latitudes. These differences in the rate of rotation within a star may have a significant role in the generation of a stellar magnetic field. In its turn, the magnetic field of a star interacts with the stellar wind. As the wind moves away from the star its angular speed decreases. The magnetic field of the star interacts with the wind, which applies a drag to the stellar rotation. As a result, angular momentum is transferred from the star to the wind, and over time this gradually slows the star's rate of rotation. Measurement Unless a sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Effective Temperature
The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature when the body's emissivity curve (as a function of wavelength) is not known. When the star's or planet's net emissivity in the relevant wavelength band is less than unity (less than that of a black body), the actual temperature of the body will be higher than the effective temperature. The net emissivity may be low due to surface or atmospheric properties, such as the greenhouse effect. Star The effective temperature of a star is the temperature of a black body with the same luminosity per ''surface area'' () as the star and is defined according to the Stefan–Boltzmann law . Notice that the total ( bolometric) luminosity of a star is then , where is the stellar radius. The definition of the stellar radius is obviously not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosphere
The photosphere is a star's outer shell from which light is radiated. It extends into a star's surface until the plasma becomes opaque, equivalent to an optical depth of approximately , or equivalently, a depth from which 50% of light will escape without being scattered. A photosphere is the region of a luminous object, usually a star, that is transparent to photons of certain wavelengths. Stars, except neutron stars, have no solid or liquid surface. Therefore, the photosphere is typically used to describe the Sun's or another star's visual surface. Etymology The term ''photosphere'' is derived from Ancient Greek roots, φῶς, φωτός/''phos'', ''photos'' meaning "light" and σφαῖρα/''sphaira'' meaning "sphere", in reference to it being a spherical surface that is perceived to emit light. Temperature The surface of a star is defined to have a temperature given by the effective temperature in the Stefan–Boltzmann law. Various stars have photospheres of vari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sun's Luminosity
The solar luminosity () is a unit of radiant flux ( power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxies and other celestial objects in terms of the output of the Sun. One nominal solar luminosity is defined by the International Astronomical Union to be . This corresponds almost exactly to a bolometric absolute magnitude of +4.74. The Sun is a weakly variable star, and its actual luminosity therefore fluctuates. The major fluctuation is the eleven-year solar cycle (sunspot cycle) that causes a quasi-periodic variation of about ±0.1%. Other variations over the last 200–300 years are thought to be much smaller than this. Determination Solar luminosity is related to solar irradiance (the solar constant). Slow changes in the axial tilt of the planet and the shape of its orbit cause cyclical changes to the solar irradiance. The result is orbital forcing that causes the Milankovitch cycles, which determine Eart ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
